The present invention relates in general to so-called xe2x80x9cmultiplexedxe2x80x9d control of the switching on and off of lighting or signalling lamps for motor vehicles.
The principles of such multiplexed control whereby a single control signal conveys on/off instructions for a plurality of independent light functions, and a bus conveying said control signal together with a single power supply line travels round the various lighting and signalling devices, are known, in particular from FR-A-2 154 209, DE-A-2 809 763, and EP-A-0 217 762. However, those documents describe only the electrical and electronic principles of such control.
Attempts have recently been made to improve the integration of electronic circuits associated with that type of control in signal light blocks. Document FR-A-2 654 996 describes one such attempt.
The present invention seeks to propose other ways of achieving such integration that are practical and cheap to implement.
To this end, the present invention provides an electrical module, in particular for a block of signalling lights for a motor vehicle, the module comprising, in combination:
a lamp-carrier implementing a plurality of recesses used as sockets for lamps;
an electronic circuit for processing a control and switching signal to selectively switch on and switch off lamps received in the sockets as a function of instructions contained in the control signal;
a printed circuit carrying said electronic circuit;
electrical power link means between the electronic circuit and the sockets; and
means for associating the lamp-carrier with the printed circuit and for establishing an electrical connection between said printed circuit and the electrical power link means.
Advantageous, but optional, aspects of the module of the present invention are the following:
the lamp-carrier is in the form of a plate including conductive tracks on one side constituting the electrical power link means, and a housing on the opposite side in which mounting means are provided for the printed circuit carrying said electronic circuit, and said printed circuit carries contacts that extend parallel to an insertion and extraction direction for said printed circuit and suitable for passing through said lamp-carrier to be electrically connected to said tracks;
said insertion and extraction direction for the printed circuit is essentially perpendicular to a general plane of said lamp-carrier;
the module further comprises a cover for closing said housing, an opening being formed in the cover to give access to a connector for electrical control and power supply purposes mounted on said printed circuit;
the lamp-carrier is in the form of a plate including on one side conductive tracks constituting the electrical power link means and on the opposite side means forming abutments for the printed circuit, the printed circuit extends essentially parallel to a general plane of said lamp-carrier, electrical connection means are provided between said conductive tracks and said electronic circuit, which means extend essentially transversely to the printed circuit and to lamp-carrier, passing through the lamp-carrier for electrical connection with said tracks, and a housing is also provided mounted on the lamp-carrier and defining counter-abutments for the printed circuit;
connection means adaptable to constitute a connector for connecting a conventional bundle of individual power supply conductors for said lamps in the absence of the electronic circuit;
a control and power supply connector is also provided including contacts mounted on the printed circuit and passing through the housing, the housing including fittings that define a cavity for receiving said contacts;
the lamp-carrier possesses means forming a bearing surface for said printed circuit in register with said control and power supply connector;
the printed circuit also constitutes a lamp support plate, the electrical power link means are carried by said printed circuit, and add-on sockets are also provided on the same side as the components of said electronic circuit and are soldered to the printed circuit;
a housing is also provided that includes fittings enabling it to be mounted on the module by co-operating with associated fittings formed on the add-on sockets;
said fittings are snap-fastening fittings;
a control and power supply connector is also provided including contacts mounted in the thickness of the housing and connected to the printed circuit, said housing including fittings that define a cavity for receiving said contacts;
said fittings bear against the printed circuit in the vicinity of the contacts;
the printed circuit is a double-sided printed circuit, the components of the electronic circuit are surface-mount components, and the sockets and the contacts of the connector are soldered to the printed circuit on its side opposite from the components;
the printed circuit is a single-sided printed circuit, the components of the electronic circuit are through mount components, and the portions of the components, of the sockets, and of the contacts of the connector that are to be soldered all project from the same side of the printed circuit, which side is opposite from the components, thereby making it possible to use a single wave soldering operation;
each socket includes a body of insulating material and at least two conductor members carried by the body, each conductor member projecting at one end into a cavity defined by said body for receiving the base of a lamp, and at its opposite end into the vicinity of a surface of the body that bears against the printed circuit and that is in alignment with said surface, thereby enabling electrical connections to be made with the socket by reflow soldering while simultaneously making connections with the components of the electronic circuit by reflow soldering;
said bearing surface of the socket body includes a groove for receiving a sealing ring;
said other ends of the conductor members project outwards relative to a base region of the body that defines said bearing surface;
each socket body includes fittings suitable for cooperating with associated fittings provided on the printed circuit for holding said socket body prior to reflow soldering;
a housing is also provided that is glued to the periphery of the printed circuit;
a control and power supply connector is also provided including a base holding captive a plurality of contacts of the connector, said base having a bearing surface pressing against the printed circuit and said contacts being disposed flush with said bearing surface to enable an electrical connection to be made with said base by reflow soldering simultaneously with the electrical connections with the components of the electronic circuit themselves being made by reflow soldering, said base defining a cavity in which the contacts of the connector are received;
the base of the connector includes fittings suitable for co-operating with associated fittings provided on the printed circuit for holding said base prior to reflow soldering;
said housing includes an opening in register with said cavity defined by the base;
the housing is soldered to said base in the vicinity of said opening; and
the housing has, in register with each add-on socket, a fitting bearing against a face of said socket that is opposite from the printed circuit.